Method of making two-piece valves



March 27, 1 928.

W. H. WASHBURNE METHOD OF MAKING TWO-PIECE VALVES I Original Filed March 10. 1924 IINVEN TOR. I #64 WW A TTORNEY jshape'of a valve head while surrounding the cold stem. During the forging or pressing Patented Mar. 27, 1928.

v UNITED STATES WILLIAM H. 'WALSVHBURNE, or CHICAGO, ILLInoIs, AssIenoR, :BY MESNE ASSIG mnNrs, T0 MOTOR vALvEs, nc, or woons'rocx, ILLINoIs, A CORIQRATION or DELAWARE.

In my rior application, Serial No. 509; ctober 24, 1921, I have disclosed a novel process by means of which a head may be forged on the end of a finished .valve stem, producing a product which requires'only the grinding of the valv'e face on the head 1n order completely to finish the valve. In carrying out my aforesaid process-I employ a washer like blank, the'hole inwhich is somewhat larger in diameter than the stem; the heated blank being pressed into the operation "the metal toward the top of the blank, if the hole in the blank is cylindrical, comes in contact with the valve stem before the lower portion of the'hole' in the blank is I 7. closed sufficiently to bring about contact between the stem and the metal near the bottom of the blank, and-heavy pressure'is required'to bring about the complete closing of the'lower end of the hole in the blank. 1 It sometimes occurs, in the manufacture of valves havingsmall stems,,that the pressure required to. insure perfect contact between the metalnear the underside of the head and thestem is so great that the stem will be damaged "and, at times, cut completely'in two. This difliculty may be ameliorated somewhat by making the hole in the blank 'in' the shape of .a frustum of a cone, the larger'end being atfthe top; but it is not feasible, by "a simple punching operation, to I secure the necessary taper to the hole to avoid thedanger of injury to the valve stems in the'process of manufacturing valves hav- 'ing very small; stems. Since the most important advantage of the aforesaid process lies. in the cheapness with which finished valves can be made, it is not desirable to add to'the 'expense of manufacture by drilling or reaming aconical hole in the blank.

Furthermore, while the foregoing difliculties do not seemtobe encountered in the amount of working of the metal in the blank for the head during the step of attaching the head to the finished valve stem. This end canbe attained by givingthe blankas nearly as maybe the shape of afinished head,

mnrnonor MAKING TWO-PIECE vALvEs.

" Application fi led marc 10, 1924, Serial No. 'e9s,145.. Renewed September 10, 1927.

before it is -applie'd to the stem. This an conveniently be accomplished by forging the head about a mandrel in the same (lies that are employed to attach the head to thestem.

properly shaping the hole'in the blank or in preforming theblank so that itwillhave substantially theshape of a finished head, or both, by a simple forging operation.

ob novel improvement in the process of manu- Iacturmg two-piece valves, which consists in Viewed in another of its aspects, my invention may be said to have for its object to improve the process of forging a head on a fimshed valve stem by using the same dies,

first to preshape the blank,and then to work it only sufiicientlyto close the hole therein upon the valve stem.

The various features of novelty whereby my. 1nventi0n is characterized will hereinafter he pointed out with particularity in the claims; but fora full understanding of my invention and of its objects and advantages,

the accompanying drawing, wherein:

reference may be had to the following de- Figure lis" a verticalsection through a pair of dies in the act of closing upon a blank for the purpose of preshaping it; Fig. 2 1s' a view similar to Fig. 1 showing the dies. closed on the blank; Fig. 3 is a view the lower die, with the preformedrblank surrounding the upper end of the same and the mandrel removed from the upper die; and,

Fig. 4= is a view similar to Fig. 3,. showing the dies "closed on the blank so as firmly to unite it to the stem. I

Referring to the drawing, 1. and 2 represent respectively a ,lower and an upper. die, the lower die having therein a cavity 3 of the exact size and shape of the valve head similar to Fig. 1, showing a valve stem in.

to be produced. The die cavity forms .the bottom ofa chamber l'into which the upper die is ada ted to descend durino the for in a C; t?

operation. The lower die has an opening or passage extending downwardly through the same from the center of the die cavity; this bore or passage being of the proper diameter to cause a finished ground valve stem to be a sliding lit therein. The upper die has in the under side thereof a pocket or recess 6 somewhat largerin diameter than the passage at, for the purpose of providing a clearance between the upper die and the forge it into the shape of a finished head, as

indicated at B in Fig. 2, excepting only that the hole in the center of'the blank willhave the shape of the conical section of a mandrel.

Vfhen the blank has to be attached to a stem, the mandrel is removed from the upper 'die,fthe stem C is inserted in the bore or passage S in the lower blank, and the preformed head, heated to a suitable temperature, is dropped. into the die cavity so as to surround that portion of the stem which projects into the cavity, as illustrated in Fig. 3. lhe stem mayrest at its lower end upon a suitable block 10 yieldably supported upon a spring 11 which may be adjusted by means of a vertically adjustable plug 12 in the lower end of the lower die. By this means the stem may be yieldably supported so as to project just the proper distance into the die cavity. The dies are thenclosed to bring about the condition illustrated in Fig. i, in which the under surface of the head retains the shape given by the first opera tion of forging the initial blank, while the thickness will have been slightly reduced to cause the metal of the blank to fiowinwardly into intimate contact with the stem. In Fig. 4 the stem is indicated at C and the head at D. At the end of the forging step illustrated in Fig. 4, the complete valve is removed from the dies and the head cooled before the stem is given an opportunity to 7 become objectionably heated.

V The upper end of the stem will usually be provided with one or more transverse external shoulders, conveniently produced by cutting one or more annular grooves into the stem, as indicated at it; so that during the final forging operation the metal of the head entersthe grooves and mechanically interlocks the head and the stem.

stantially the same diameter as the stem, so that in the final forging operation the metal adjacent to the under face of the valve will receive little or no working, the closing of the hole being caused by a slight downward and inward movement of the metal in the upper portions of the valve. In the drawing I have exaggerated the size of the conical hole in order to make the principle of my invention clear; but, 1n actual practlce, since the. work of making the preshapedhead may be done very accurately, the taper and the clearance will be slight.

While I have illustrated and described with particularity only a single preferred form of my invention, I do not desire to be limited to the exactstructural details thus without exerting any forging pressure on.

the stem in the direction of its length.

2. The method of making a two-piece valve which consists in forging a blank in dies to give it the shape of a valve head having a central hole slightly larger than a stem to which the head is to'be applied, and then placing astem in said hole and forging the head in the aforesaid dies to unite the head and the stem.

3. The method of making a two-piece valvewhich consists in forging a blank in dies about a mandrel to give it the shape of a finished valve head but of a slightly greater thickness than the latter and having a central hole therethrough slightly larger than a stem, removing the mandrel and substituting therefor a valve stem, and then again forging the head in the aforesaid dies to unite the head tothe stem.

4. The. method of making a two-piece valve which consists in forging a blank to give it the shape of a valve head having a. central hole therethrough increasing somewhat in diameter fromthe bottom toward the top, inserting a valve stem into said hole,

and then forging the blank by pressure exerted solely on the blank, while the stem is left free from any forging pressure in the direction of its length, to unite the head to the stem.

5. The method of making a two piece valvev which consists in forging a blank to give it the shape of a valve head having a 1,668,784 a g 8 I central hole of approximately the same dileft free from any forging pressure in the ameter at its lower end as the diameter of a direction of its length, to cause the metal of stem to which the head is to be attached and the head to flow inwardly into intimate con- 10 increasing gradually in diameter toward the tact with the stem.

top, inserting a valve stem intosaid hole, In testimony whereof, I sign this specifiand then forging the head by a pressure 8X cation; erted solely on the same, while the stem 1s WILLIAM H, WASHBURNE; 

